Liquid fuel burning appliance and components therefor



Dec. 23, 1969 J. Qf f ET AL 3,485,567

LIQUID FUEL BURNING APPLIANCE AND COMPONENTS THEREFOR Filed Jan. 26,1968 five-2125015 lam/441,4

United States Patent 3,485,567 LIQUID FUEL BURNING APPLIANCE ANDCOMPONENTS THEREFOR Joseph Hutchinson, Jefferson City, and Lloyd Casey,

Macon, M0,, assignors to McGraw-Edison Company,

Elgin, Ill., a corporation of Delaware Filed Jan. 26, 1968, Ser. No.700,955 Int. Cl. F23d 11/00; F23n 1/00 US. Cl. 431-210 Claims ABSTRACTOF THE DISCLOSURE This invention relates to a liquid fuel firedappliance that requires the liquid fuel first to be vaporized before itis ignited and burned, and more particularly, to improved componentstherefor including a fuel control valve and a fuel tank. The particularvalve has a single control member suitable in one position forcompletely closing the valve to shut off the appliance, suitable inanother position for delivering a highly vaporous mixture of gasolineand air to the appliance for initial igniting thereof, suitable in stillanother position for delivering liquid fuel which can be vaporized bythe heat of combustion to the appliance for sustained operation atvariable outputs. The subject fuel tank provides air pump and checkvalve components that can be readily assembled or disassembled forimproved reliability.

Portable camping stoves, lanterns and other appliances commonly burn aliquid gasoline fuel which must first be vaporized before it iscombusted. Initial igniting of the fuel is a problem with appliances ofthis type since the liquid fuel has little tendency to vaporizecompletely and excessive liquid fuel commonly can be delivered to theappliance before reliable combustion occurs. Consequently, seriousaccidents can occur during the starting of gasoline fired appliances,caused mainly by flashing of the excessive liquid gasoline. Moreover,improper maintenance of major components of the appliance, such as theair pump and check valve, impairs both the safety and the efiicientoperation of the appliance.

Accordingly, an object of this invention is to provide in a liquid fuelfired appliance a fuel control valve that can be moved to one positionto permit easy initial starting of the appliance and yet can be moved toanother position for smooth sustained operation of the appliance afterit has been once started.

A more detailed object of this invention is to provide an improved fuelcontrol valve having a single control member that discharges abundantvaporous fuel from a. fuel tank to a mixing carburetor for initiallystarting the appliance, and that discharges liquid fuel only from thefuel tank after the initial ignition for sustained operation of theappliance.

Another object of this invention is to provide in a gasoline firedappliance an improved fuel tank having respective components includingan air pump and check valve that are readily disassembled and assembledto provide for easy cleaning and/ or replacement of the components.

These and other objects will be more fully understood and appreciatedafter referring to the following specification, including theaccompanying drawing which forms a part thereof, wherein:

Patented Dec. 23, 1969 FIG. 1 is a perspective view of a typical gasfired appliance in the form of a camping stove incorporating the subjectinvention;

FIG. 2 is a side elevation view, partly in section, of the camping stoveshown in FIG. 1, except with the cover closed;

FIG. 3 is an enlarged sectional view, as seen generally from line 3-3 inFIG. 1, of the subject control valve; and,

FIG. 4 is an enlarged section view, as seen generally from line 4-4 inFIG. 1, of the subject fuel tank.

In the drawing, a portable camp stove 10 is shown which includes an opentop body 12 and a cover 14 pivoted thereto by means of hinges 16 whichwhen closed forms a generally boxlike structure (FIG. 2) and when openedexposes a grate 18 overlying spaced burners 20 and 21. Deflectors 24 arepivoted to the underside of cover 14 and can be swung out from theposition shown in FIG. 1 to a position generally parallel to end walls26 of the body 12 to shield the burners from the wind. A fuel tank 28 isreleasably held to the body 12 by clips 30 received within openings infront wall 32 of the body, and a hollow conduit 34 communicates from thefuel tank through carburetor 36 and pipes 38 to the burner 20. The twoburners 20 and 21 are connected together by pipe 40, with a valve 42therein regulating the flow of combustible fuel mixture from burner 26to the burner 21.

One feature of this invention is the fuel control valve 50 located onthe fuel tank 28 in series connection with the conduit 34. The valve 50includes a T-shaped housing 52 (FIG. 3) having leg portion 54 threadedfor sealing connection within a tap on the fuel tank 28. A cavity 56 isformed within the housing, and two tubes 58 and 60 are connected to thehousing and communicates between the cavity and fuel tank 28'. Tube 58is relatively short so that its lower open end is spaced above the topsurface 62 (FIG. 2) of liquid fuel within the tank; whereas tube 60 isquite long to present its lower open end below the surface of liquidfuel in the tank and preferably adjacent the bottom of the tank. Thecavity 56 communicates through passageway 63 and the conduit 34 with thecarburetor 36.

A valve member 64 is received within the housing 52 and movable axiallytherein upon rotation because of the cooperating threads 66. The valvemember presents a portion 68 within the cavity and an elongated stem orthrottle section 70 that extends completely through the conduit 34 intoan orifice 72. Portion 68 of the valve member defines a number of valveareas each designed to perform a particular function as follows.Initially, first valve area 76 is adapted to seat over and blockpassageway 63 between the cavity 56 and the carburetor 36 when valvemember 64 is threaded completely into the housing 56. This closes thevalve and shuts the appliance off. The second valve area 80 cooperateswith port 82 connecting the liquid fuel tube 60 to the cavity 56, thevalve area being located somewhat downstream of the port when the valveis closed. The valve area 80 does not seat against the peripheralhousing walls of the cavity 56, but merely restricts the passage offluid past these locations. A tapering third valve area 84 cooperateswith port 86 connecting the air tube 58 to the cavity 56. A ball check88 is located in housing passageway 89 to the tube 58, and is normallymaintained by spring 92 against the valve seat to close the passageway.A push rod or spacer element 94 is receiver within passageway 89 and isadapted to engage the ball check 88 and to ride on the third valve areaor cam surface 84 of the valve member 64.

When the valve 64 is closed, rod 94 is on a high side of valve area 84to maintain passageway 89 opened for communicating the vaporous sectionof the fuel tank 28 with cavity 56. Upon opening the valve, first valvearea 80 opens passageway 63, and the high surface of valve area 84engaging the rod 94 maintains ball check 88 open to communicate thevaporous section of the fuel tank 28 with the conduit 34 and thecarburetor 36. Fuel is also permitted to flow from the fuel tank throughthe liquid tube 60 past the restricted valve area 80, but since thesecond valve area 80 still partially overlaps the port 82 from thistube, much of the fuel flow will be through the gas tube 58 and not theliquid tube 60. This vaporous fuel flow is readily combusted for initialstarting of the burner 20.

The conduit 34 overlies and receives heat from the burner 20, so thatafter the burner is ignited the heated conduit vaporizes any fueltherein for sustained operation. In this regard, a metallic coil spring100 is fitted loosely around the stem 70 within the conduit, which whenheated, adds surface area for more completely vaporizing the liquidgasoline passing through the conduit.

Continued withdrawal of the valve member 64 provides that rod 94 ridesoff the tapered section on the valve area 84 to close the ball check 88and block off the gas tube 58 from the cavity 56. Conversely, the secondvalve area 80 progressively passes the port 82 from the liquid tube 60to permit freer unrestricted flow of liquid fuel to the cavity. The fuelflow is controlled by the valve area 80 clearing the port 82 from theliquid tube 60 and main valve area 76 separating from its cooperatingseat. The stem 74 within the orifice 72 provides controlled discharge ofthe gaseous fuel to the carburetor, and since the stern tip within theorifice is tapered, withdrawal of the valve member 64 increases theorifice opening to admit a greater quantity of vaporous fuel to theburner.

It is readily understood that the appliance would be started bywithdrawing the valve member the particular distance required, such asby rotating it one quarter of a turn from its closed position, to openthe starting gas tube and the main valve opening. After the appliancehas been fired for a time sufficient to heat the conduit to vaporize theliquid fuel therein, the valve member is withdrawn further to itsregular operating condition which closes the gas tube and maintainsliquid fuel discharge as required for the appliance output.

Also of concern in this invention is the fuel tank 28 and itsconstruction. Note that the fuel tank is formed with a cup shaped body106 having a threaded open section that is closed by cap 108 cooperatingwith the threaded open section. The cap 108 similarly has an opening 110and an internally threaded section 112 that extends from the opening. Acup shaped pump cylinder 114 fits within the opening 110 and has a lip116 that is restrained between the land area of the cap adjacent theopening and a plug 118 threaded into the threaded section 112. A pumppiston 120 is located within the pump cylinder 114 and is connected bystem 122 to an actuating handle 124, the stern extending through opening126 in the plug 118. The stem is hollow and communicates between thepump chamber 129 and the atmosphere at opening 130 in handle 124. Adischarge check valve unit 128 is provided from pump chamber 129, andincludes a movable valve member 132 supported to cooperate with opening134 to close the opening or to be moved from the opening for venting thechamber, and a spring 136 between the valve member 132 and the cylinder114 normally holds the valve member closed. Appropriate seals 130 and140 are confined between body 106 and cap 108, and

cap 108 and cylinder lip 116, respectively, to seal the fuel' tank.

The pump cylinder can be readily worked merely by withdrawing the handle124 without covering-the opening 130 to permit air to enter the chamber129, and then advancing the handle toward the chamber while coveringture or liquid fuel will readily be dispensed to the carburetor. Thefuel tank construction is of particular concern since the main workingcomponents can be readily disassembled for cleaning or replacing them asrequired.

What is claimed is:

1. In a liquid fuel powered appliance having a fuel tank, a carburetor,a conduit between the fuel tank and carburetor, and a burner forreceiving vaporous fuel mixture from the carburetor and burning the samefor among other things vaporizing liquid fuel for sustained operation,an improved control valve useful for both starting the appliance andcontrolling sustained operation thereafter,

comprising a housing having a cavity open to the conduit; a pair oftubes connecting the cavity with the fuel tank, one tube being open tothe fuel tank below the surface of liquid fuel therein operable to carrymostly liquid fuel and the other tube being open to the fuel tank abovethe surface of the liquid fuel therein operable to carry mostly vaporousfuel; a valve member movable in the housing to a closed positioncorresponding to an off condition of the appliance, a partially openposition corresponding to a start condition of the appliance, and anopen position corresponding to an operating condition of the appliance,and said valve member having spaced first, second and third valve areas;the valve member, when in the closed position, being operable tocompletely close the conduit between the fuel tank and carburetor bymeans of the first valve area seating against a main valve seat in thehousing and being operable by means of the third valve area to open theother tube to the cavity; the valve mem her, when partly open or in thestart condition of the appliance, being operable to open the conduitbetween the fuel tank and carburetor, being operable to partially blockthe one tube by means of the second valve area to permit only limitedrestricted flow of liquid fuel to the cavity, and being operable bymeans of the third valve area to maintain the other tube to the cavityopen to permit substantially unrestricted flow of mostly vaporous fuelto the carburetor for initial starting of the appliance; and the valvemember, when open or in the operate condition of the appliance, beingoperable by means of the third valve area to close the other tube to thecavity, and being operable by means of the second valve area to maintainopen the one tube for continued flow of mostly liquid fuel to thecavity.

2. A liquid fuel powered appliance control valve according to claim 1,wherein a check valve is located in the other tube between the fuel tankand cavity and is normally maintained in the closed position, andwherein means disposed between the check valve and third valve area onthe valve member maintain the check valve open and thus open the othertube only when the valve member is in the closed and the partially openpositions.

3. A liquid fuel powered appliance control valve according to claim 1,further including a stern connected to the valve member and extendingthrough the conduit to within an orifice disposed adjacent thecarburetor, and wherein the stem has a tapered nose section receivedwithin and cooperating with said orifice in the various operativepositions of the valve member to meter proper volumes of vaporous fuelair mixture to the carburetor.

4. A liquid fuel powered appliance control valve according to claim 3,further including a coil element loosely surrounding the stem anddisposed within' the conduit operable.- to be heated duringsustainedoperation of the burner to provide fuel.

5. A liquidfuel powered appliance control valve ac-' cording to claim 1,wherein said second valve area is substantially cylindrical and overliesa port from the one tube open to the cavity so that movement of thevalvemember from the closed to the open positions gradually and progressivelyuncovers the port. 7

6. A liquid fuel powered appliance control valve according to claim 1,wherein said third valve area includes large heated surfaces forvaporizing the" a tapered cam surface, wherein a check valve is in theother tube and is normally held closed, and wherein a pusher rod rideson the cam surface as the valve member is at its respective partiallyopen position and engages and holds the check valve open.

7. In a liquid fuel powered appliance having a fuel tank, a carburetor,a conduit between the fuel tank and carburetor, and a burner forreceiving vaporous fuel mixture from the carburetor and burning the samefor among other things vaporizing liquid fuel for sustained operation,an improved control valve useful for both starting the appliance andcontrolling sustained operation thereafter, comprising a housing havinga cavity open to the conduit; a pair of tubes connecting the cavity withthe fuel tank, with one tube being open to the fuel tank below thesurface of liquid fuel therein operable to carry mostly liquid fuel andwith the other tube being open to the fuel tank above the surface of theliquid fuel therein operable to carry mostly vaporous fuel; a valvemember movable in the housing to a closed position corresponding to anoff condition of the appliance, whereat the conduit between the fueltank and carburetor is completely closed; said valve member also beingmovable to a partially open position corresponding to a start conditionof the appliance, whereat both the conduit between the fuel tank andcarburetor and the other tube are opened to permit abundant flow ofmostly vaporous fuel to the carburetor; and the valve member furtherbeing movable to an open position corresponding to sustained operationof the appliance, whereat the conduit between the fuel tank andcarburetor and the one tube are both opened and the other tube is closedto permit flow of mostly liquid fuel to the carburetor.

8. In a liquid fuel powered appliance having fuel tank, a carburetor, aconduit between the fuel tank and carburetor, and a burner for receivingvaporous fuel mixture from the carburetor for burning the same for amongother things vaporizing liquid fuel for sustained operation, an improvedfuel tank comprising a cup shaped body having an open end, and a capremovably threaded to the body across the open end; a cup shaped airpump cylinder extending into the fuel tank from an opening in the capand having an open end exposed to the exterior of the fuel tank, meansincluding a lip on the cylinder confined against the cap, and a plugconfined against the lip and threaded into the open end of said cap forremovably securing and sealing the cylinder to the fuel tank; a pistonin the air pump cylinder defining a chamber, a rod connected to thepiston and extending through an opening in said plug to the exterior ofthe fuel tank and being manipulated to move the piston, and a normallyclosed outlet check valve from the chamber to the interior of the fueltank; and a control valve mounted on and communieating with the fueltank for metering fuel to the carburetor.

9. A liquid fuel powered appliance fuel tank according to claim 8,wherein the rod is hollow and communicates between the air pump chamberand the exterior of the fuel tank and has an end opening outside thefuel tank, and wherein said hollow rod acts as an inlet check valve tothe air pump chamber by selectively manually covering and uncovering theopen end of the rod during the' manipulation of the rod incident tomoving the piston.

10. A liquid fuel powered appliance, comprising in combination acarburetor; a burner for receiving vaporous fuel mixture from thecarburetor and. burning the same; a fuel tank including a cup shapedbody having an opened end and a cap removably secured to the body acrossthe open end; an air pump indcluding a cup shaped cylinder extendinginto the fuel tank from an opening in the cap, a plug across the openend of the cap for removably securing and sealing the cylinder to thefuel tank, a piston in the cylinder defining an air pump chamber, a rodconnected to the piston and extending through an opening in said plug tothe exterior of the fuel tank and being manipulated to move the piston,and a normally closed outlet check valve from the chamber to theinterior of the fuel tank; a conduit between the carburetor and fueltank; and a flow control valve including a housing supported on the fueltank and having a cavity opened to the conduit, a pair of tubesconnecting the cavity with the fuel tank, with one tube extending belowthe surface of liquid fuel therein and with the other tube extendingonly to above, the surface of the liquid fuel therein, a valve membermovable in the housing, said valve member being movable to a firstposition corresponding to an oif condition of the appliance whereat theconduit is completely closed, said valve member also being movable to asecond position corresponding to a start condition of the appliancewhereat the conduit and. the other tube are both opened to permitabundant flow of mostly vaporous fuel to the conduit, and the valvemember further being movable to a third position corresponding tosustained operation of the appliance whereat the conduit and the onetube are both opened and the other tube is closed to permit flow ofmostly liquid fuel to the conduit.

References Cited UNITED STATES PATENTS 3/1931 Schmidt 43 l234 X 1/1938Yeager 126-38 US. Cl. X.R. 126-38; 431 234

